This invention is related to the catalytic treatment in the presence of hydrogen of hydrocarbon streams containing large concentrations of nitrogen compounds to remove nitrogen compounds therefrom and the catalyst useful therein.
In U.S. Pat. No. 4,181,602, Quick, et al., disclose a process for the hydrotreating of a heavy hydrocarbon stream wherein said stream is contacted under suitable conditions and in the presence of hydrogen with a catalyst comprising (1) the metals of molybdenum, chromium, and cobalt, (2) their oxides, (3) their sulfides, or (4) mixtures thereof on a large-pore, catalytically-active alumina, said molybdenum being present in an amount within the range of about 5 wt% to about 15 wt%, calculated as MoO.sub.3 and based upon the total catalyst weight, said chromium being present in an amount within the range of about 5 wt% to about 20 wt%, calculated as Cr.sub.2 O.sub.3 and based upon the total catalyst weight, said cobalt being present in an amount within the range of about 0.1 wt% to about 5 wt%, calculated as CoO and based upon the total catalyst weight, and said catalyst possessing a pore volume within the range of about 0.4 cc/gm to about 0.8 cc/gm, a surface area within the range of about 150 m.sup.2 /gm to about 300 m.sup.2 /gm, and an average pore diameter within the range of about 100 .ANG. to about 200 .ANG..
In U.S. Pat. No. 4,224,144, Hensley, Jr., et al., discloses the catalytic hydrotreatment of petroleum distillates and similar hydrocarbon materials in the presence of a catalyst comprising a hydrogenation component comprising chromium, molybdenum, and a Group VIII metal deposited upon a porous refractory inorganic oxide support or carrier, such as alumina, silica-alumina, silica, magnesia, zirconia, and similar materials. They disclose that such a catalyst and process can be used successfully to remove nitrogen and sulfur from a hydrocarbon stream selected from petroleum distillates, tar sands distillates, and shale oil.
In U.S. Pat. No. 4,218,308, Itoh, et al., disclose a catalyst comprising a silica-alumina carrier having a silica content that is less than about 40 wt% and at least one noble metal component of Group VIII. The catalyst contains (1) pores having a diameter of smaller than 600 .ANG. occupying at least 90% of the total pore volume and (2) pores having a diameter of 150 to 600 .ANG. occupying at least about 40% of the total volume of pores having a diameter of smaller than 600 .ANG.. They indicate that such catalyst, which is characterized further in that it has a specific surface area of at least about 200 m.sup.2 /gm and a bulk density of less than about 0.6 gm/ml, is capable of effectively removing aromatic compounds contained in a hydrocarbon oil and is useful in the production of jet fuels, kerosene, and white oils.
In U.S. Pat. No. 4,008,149, Itoh, et al., disclose a hydro-refining catalyst and its use in a process for hydro-refining heavy hydrocarbon oils containing sulfur, nitrogen, and metal contaminants. The catalyst comprises one or more metals selected from the metals of Groups VI and VIII supported on an alumina-containing carrier containing from about 5 to about 25 wt% silica. The catalyst has a specific surface area in the range of 250 to about 300 m.sup.2 /gm and a pore volume distribution characterized in that the volume of pores having a diameter of 60 to 150 .ANG. is at least about 80% of the volume of pores having a diameter of 0 to 150 .ANG., the volume of pores having a diameter of 150 to 300 .ANG. is less than about 20% of the volume of pores having a diameter of 0 to 300 .ANG., the volume of pores having a diameter of 0 to 600 .ANG. is in the range of about 0.45 to about 0.60 ml/gm, and the volume of pores having a diameter of 150 to 2,000 .ANG. is less than about 0.01 ml/gm.
Now there has been found a catalyst which comprises a hydrogenation component comprising chromium, molybdenum, and at least one metal of Group VIII and a porous alumina-silica support, which support contains silica in an amount within the range of about 10 wt% to about 50 wt%, based upon the weight of the catalyst support.